Cable sheath breakage detection method, device, equipment and readable storage medium

Abstract

The application discloses a cable sheath damage detection method, device and equipment and a readable storage medium, relates to the technical field of cable sheath damage detection, and comprises the following steps: establishing a normal sheath current calculation model and a damaged sheath current calculation model of a cable sheath; calculating the theoretical phasor value of the sheath current of a plurality of target points on the cable sheath under normal conditions; the calculation model calculates the theoretical phasor value of the sheath current of the plurality of target points on the cable sheath under different damage positions and different damage grounding resistance values, and forms a sheath damage grounding total current information atlas; whether the cable sheath is damaged is judged according to the actual phasor value and the theoretical phasor value; if the cable sheath is damaged, the damage position of the cable sheath is determined according to the actual phasor value of the sheath current of the plurality of target points and the sheath damage grounding total current information atlas. The application can accurately judge whether the cable sheath of a long cable line is damaged, and realizes accurate positioning of the damage position of the sheath.

Description

Technical Field

[0001] This invention relates to the field of cable sheath damage detection technology, and in particular to a method, apparatus, equipment and readable storage medium for cable sheath damage detection. Background Technology

[0002] The cable sheath is a crucial component ensuring the safe operation of cables, effectively preventing internal moisture, mechanical damage, and chemical corrosion. However, during long-term cable operation, the cable sheath may develop localized damage points due to aging, construction defects, or external damage. This can create a multi-point grounding structure within the cable sheath, causing excessive circulating current and accelerating the deterioration process at the damaged points. Furthermore, moisture can continuously penetrate inward from these damaged points, increasing the probability of water treeing and severely impacting the cable's operational safety and long-term service life.

[0003] The main methods for detecting cable sheath damage include temperature detection and infrared detection. Temperature detection methods primarily include point-based temperature measurement and fiber optic temperature measurement. Point-based temperature measurement involves distributing several point temperature sensors along the cable line at locations prone to failure to detect the temperature in these areas. This method can only monitor the temperature of small, localized areas and cannot achieve full coverage of long cable lines. Fiber optic temperature measurement involves laying optical fibers along the cable to detect the overall cable temperature. However, the temperature measured by this method is greatly affected by environmental factors, and its implementation on-site is complex and difficult to maintain. Infrared detection mainly relies on infrared equipment to monitor the internal condition of the sheath along the line. However, due to the complex design of infrared thermal imagers, the equipment is large and not portable, has a small measurement range, and is unsuitable for long cable lines. Therefore, the above methods are insufficient to accurately determine whether the cable sheath of long cable lines is damaged. Furthermore, when the cable sheath is damaged, these methods also struggle to pinpoint the location of the damage. Summary of the Invention

[0004] This invention provides a method, apparatus, device, and readable storage medium for detecting cable sheath damage, thereby solving the technical problems of related technologies that make it difficult to accurately determine whether the cable sheath of long cable lines is damaged, and also make it difficult to locate the location of cable sheath damage.

[0005] Firstly, a method for detecting cable sheath damage is provided, including the following steps:

[0006] Establish calculation models for normal cable sheath current and damaged cable sheath current;

[0007] The theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions are calculated based on the normal sheath current calculation model.

[0008] Based on the damaged sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath are calculated under different damage locations and different grounding resistance values, and a complete current information spectrum of sheath damage grounding is formed.

[0009] Determine whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath.

[0010] If the cable sheath is damaged, the location of the cable sheath damage is determined based on the actual phasor values ​​of the sheath current at multiple target points and the total current information spectrum of the sheath damage grounding.

[0011] In some embodiments, determining whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath includes:

[0012] The actual phasor values ​​of the sheath current at multiple target points are collected at preset time intervals. The deviation value and the average deviation value are calculated based on the actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points.

[0013] If the deviation value and the average deviation value meet the first preset condition, the average alarm deviation value is calculated based on the deviation value.

[0014] Determine whether the average deviation and the average alarm deviation meet the second preset condition: if yes, determine that the cable sheath is damaged; if no, determine that the cable sheath has experienced a single abnormal disturbance.

[0015] In some embodiments, the step of collecting actual phasor values ​​of sheath current at multiple target points at preset time intervals, and calculating deviation values ​​and average deviation values ​​based on the collected actual and theoretical phasor values ​​of sheath current at multiple target points, includes:

[0016] According to the formula:

[0017]

[0018] Calculate any t i Time deviation value S i ;

[0019] According to the formula The mean deviation S was calculated. average ;

[0020] When the power grid is cross-connected, multiple target points are the cross-grounding point and cross-connection point at both ends of a certain phase, and a certain phase I g1 I g2 I c1 I c2These are the actual phasor values ​​of the sheath current at the two cross-grounding points and the cross-interconnection points, respectively. g1_c I g2_c I c1_c I c2_c These are the theoretical phasor values ​​of the sheath current at the cross-grounding point and the cross-interconnection point at both ends of the cable sheath under normal conditions; the preset time interval can be selected according to requirements; N is the number of samplings, and i ranges from 1 to N.

[0021] In some embodiments, if the deviation value and the average deviation value meet a first preset condition, then the average alarm deviation value is calculated based on the deviation value, including:

[0022] If the deviation value and the mean deviation satisfy S N＝1 ≥2S average According to the formula The average alarm deviation S was calculated. average_warning .

[0023] In some embodiments, determining whether the average deviation and the average alarm deviation meet a second preset condition includes:

[0024] When the mean deviation and alarm deviation meet S average_warning <2S average If the mean deviation and the mean alarm deviation satisfy the second preset condition, then the second preset condition is determined.

[0025] In some embodiments, if the cable sheath is damaged, determining the location of the cable sheath damage based on the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding total current information spectrum includes:

[0026] The theoretical phasor values ​​of the sheath current at multiple target points in the sheath damage and grounding full current information spectrum under different damage locations and different grounding resistance values ​​are used to form a data set.

[0027] Establish the minimum current norm I for sheath failure d Relationship:

[0028]

[0029] Among them, I g1_d I g2_d I c1_d I c2_d This represents the theoretical phasor value of the sheath current at a specific location and with a specific grounding resistance value within the dataset.

[0030] According to I d The minimum value determines the location of cable sheath damage.

[0031] In some embodiments, establishing the calculation model for the normal sheath current and the calculation model for the damaged sheath current of the cable sheath includes:

[0032] The calculation model for normal sheath current of cable is established as follows:

[0033] I i =I is +I ic ;

[0034] Among them, I i This represents the sheath current at the target point under normal cable sheath conditions.

[0035] I is This represents the leakage current at the target point under normal cable sheath conditions.

[0036] I ic This refers to the induced current at the target point under normal cable sheath conditions.

[0037] The calculation model for cable sheath damage current is established as follows:

[0038] I if =I isf +I icf ;

[0039] Among them, I if This refers to the sheath current at the target point when the cable sheath is damaged.

[0040] I isf This refers to the leakage current at the target point when the cable sheath is damaged.

[0041] I icf This refers to the induced current at the target point when the cable sheath is damaged.

[0042] Secondly, a cable sheath damage detection device is provided, comprising:

[0043] Modeling unit, which is used to establish a calculation model for normal sheath current and a calculation model for damaged sheath current of cable sheath;

[0044] The first calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath according to the normal sheath current calculation model.

[0045] The second calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different damage grounding resistance values ​​based on cable parameters, load current and damaged sheath current calculation model, and form a complete current information spectrum of sheath damage grounding.

[0046] The judgment unit is used to determine whether the cable sheath is damaged based on the actual phasor value and theoretical phasor value of the sheath current at multiple target points;

[0047] The positioning unit is used to determine the location of cable sheath damage based on the actual phasor values ​​of sheath current at multiple target points and the sheath damage grounding full current information spectrum if the cable sheath is damaged.

[0048] Thirdly, a computer device is provided, comprising: a memory and a processor, wherein the memory stores at least one instruction, the at least one instruction being loaded and executed by the processor to implement the aforementioned cable sheath damage detection method.

[0049] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions, which, when executed by a computer, cause the computer to perform the aforementioned cable sheath damage detection method.

[0050] The beneficial effects of the technical solution provided by this invention include:

[0051] This invention provides a method, apparatus, device, and readable storage medium for detecting cable sheath damage. First, a calculation model for the normal sheath current and a calculation model for the damaged sheath current are established. Then, based on the normal sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions are calculated. Next, based on the damaged sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath are calculated under different damage locations and different grounding resistance values, forming a complete current information spectrum of sheath damage grounding. Then, based on the actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath, it is determined whether the cable sheath is damaged. Finally, if the cable sheath is damaged, the location of the cable sheath damage is determined based on the actual phasor values ​​of the sheath current at multiple target points and the complete current information spectrum of sheath damage grounding. This invention can accurately determine whether the cable sheath of a long cable line is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath. Then, by using the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum, the location of the cable sheath damage can be determined, thus achieving accurate location of the sheath damage. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a flowchart illustrating a cable sheath damage detection method provided in an embodiment of the present invention.

[0054] Figure 2 A power grid structure diagram showing the cross-interconnection method provided in an embodiment of the present invention;

[0055] Figure 3 Phase curves of sheath current under different damage locations and different grounding resistance values ​​provided in embodiments of the present invention;

[0056] Figure 4 The sheath current amplitude curves under different damage locations and different grounding resistance values ​​provided in this embodiment of the invention;

[0057] Figure 5 This is a schematic diagram of the structure of a cable sheath damage detection device provided in an embodiment of the present invention;

[0058] Figure 6 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] This invention provides a method for detecting cable sheath damage, which solves the technical problem that existing related technologies are unable to accurately determine the damage state of cable sheaths or accurately determine the location of damage.

[0061] See Figure 1 As shown, this embodiment of the invention provides a method for detecting cable sheath damage, including the following steps:

[0062] Step S10: Establish the calculation model for normal sheath current and the calculation model for damaged sheath current of the cable.

[0063] Specifically, the calculation model for the normal sheath current of the cable sheath is established as follows:

[0064] I i =I is +I ic ;

[0065] Among them, I iThis represents the sheath current at the target point under normal cable sheath conditions.

[0066] I is This represents the leakage current at the target point under normal cable sheath conditions.

[0067] I ic This refers to the induced current at the target point under normal cable sheath conditions.

[0068] The calculation model for cable sheath damage current is established as follows:

[0069] I if =I isf +I icf ;

[0070] Among them, I if This refers to the sheath current at the target point when the cable sheath is damaged.

[0071] I isf This refers to the leakage current at the target point when the cable sheath is damaged.

[0072] I icf This refers to the induced current at the target point when the cable sheath is damaged.

[0073] Specifically, the sheath current generation is analyzed using a dual PI structure. According to the current generation mechanism, currents are generated in a closed loop due to electric and magnetic fields, namely leakage current and induced current. In other words, the sheath current consists of two parts: leakage current and induced current.

[0074] 1. For cable sheath under normal conditions

[0075] Leakage current calculation model: First, calculate the total leakage current using the phase voltage and the capacitance current to ground. Then, based on the ratio of the length of the target point on the left and right sides of the cable, calculate the leakage current value at each location after current shunting. The calculation formula is as follows:

[0076] I is =I s ·L2 / L1

[0077] I is I represents the leakage current at the target point. s L1 represents the total leakage current, and L2 represents the length of the target point on the left and right sides of the cable.

[0078] Induced current calculation model: The induced voltages generated by the sheath current, load current, and leakage current of other phases are superimposed to obtain the total sheath induced voltage. This total voltage is then divided by the sheath impedance matrix to obtain the sheath induced current. The calculation formula is as follows:

[0079] I ic =inv(Z)·(Uh +U LD +U S )

[0080] I ic U represents the induced current at the target point, Z represents the sheath impedance matrix, inV(Z) represents the inverse of the sheath impedance matrix Z, and U represents the inverse of the sheath impedance matrix Z. h U represents the induced voltage of the other phase sheath current. LD The induced voltage, U, represents the load current. S The induced voltage represents the leakage current.

[0081] The leakage current I at the above different locations is and induced current I ic By adding them together, the sheath current at different locations can be obtained.

[0082] 2. Regarding cable sheath damage

[0083] Leakage current calculation model: First, the total leakage current is calculated from the phase voltage and the capacitance current to ground. For non-damaged phases, the current shunt can still be calculated by the ratio of the length of the target point on the left and right sides of the cable. For damaged phases, since there is a grounding branch, the current shunt needs to be calculated based on the ratio of the impedance (considering the grounding resistance) of the target point on the left and right sides of the cable.

[0084] I isf =I s ·Z2 / Z1

[0085] I is I represents the leakage current at the target point. s Z1 and Z2 represent the total leakage current, and Z1 and Z2 represent the sheath impedance of the target point on the left and right sides of the cable after considering the fault branch.

[0086] Induced current calculation model: The induced voltages generated by the sheath current, load current, leakage current and fault current at the damage point are superimposed to obtain the total sheath induced voltage. Then, the total sheath induced voltage is obtained by dividing it by the sheath impedance matrix.

[0087] I icf =inv(Z f )·(U h +U LD +U S +U f )

[0088] I icf Z represents the induced current at the target point. f This represents the total sheath impedance matrix after considering the faulty branch, inv(Z) f ) represents the total sheath impedance matrix Z f Find the inverse matrix, Uh U represents the induced voltage of the other phase sheath current. LD The induced voltage, U, represents the load current. S The induced voltage, U, represents the leakage current. f This represents the induced voltage in the faulty branch.

[0089] The leakage current I at the above different locations isf and induced current I icf By adding them together, the sheath current at different locations can be obtained.

[0090] Step S20: Calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions based on the normal sheath current calculation model.

[0091] Specifically, by substituting the cable parameters and the load current of the cable sheath under normal conditions into the aforementioned normal sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions are obtained. Wherein, when the power grid is cross-connected, the multiple target points are the cross-grounding point and the cross-connection point at both ends of a phase, such as... Figure 2 As shown, taking phase A as an example, the black dots at both ends of the phase A sheath are the cross-grounding points, and the black dots in the middle of the phase A sheath are the cross-interconnection points.

[0092] Step S30: Calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different grounding resistance values ​​according to the damaged sheath current calculation model, and form a complete current information spectrum of sheath damage grounding.

[0093] Specifically, by substituting the cable parameters and the load current of the cable sheath at different damage locations and with different grounding resistance values ​​into the aforementioned damaged sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath are obtained, forming a complete current information spectrum of the sheath damage grounding, including both amplitude and phase components, such as... Figure 3 and Figure 4 As shown in the figure, the horizontal axis of the curves represents the grounding resistance, and the vertical axis represents the amplitude and phase of the sheath current. For ease of illustration, each curve represents the current distribution at 10%L intervals; in actual calculations, the 10% interval can be adjusted to a 1% interval. Here, L is the cable length, and 10%L refers to the interval between fault points, i.e. Figure 3 The distances from the fault point to the left end of the cable are 10%L, 20%L, ..., 90%L.

[0094] Step S40: Determine whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath.

[0095] Specifically, the step of determining whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath includes:

[0096] Step S401: Collect the actual phasor values ​​of the sheath current at multiple target points at preset time intervals, and calculate the deviation value and the average deviation value based on the collected actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points.

[0097] Specifically, according to the formula:

[0098]

[0099] Calculate any t i Time deviation value S i ;

[0100] According to the formula The mean deviation S was calculated. average ;

[0101] When the power grid is cross-connected, multiple target points are the cross-grounding point and the cross-connection point at both ends of a certain phase, I g1 I g2 I c1 I c2 These are the actual phasor values ​​of the sheath current at the two cross-grounding points and the cross-interconnection points, respectively. g1_c I g2_c I c1_c I c2_c These are the theoretical phasor values ​​of the sheath current at the cross-grounding point and the cross-interconnection point at both ends of the cable sheath under normal conditions; the preset time interval can be selected according to requirements; N is the number of samplings, and i ranges from 1 to N.

[0102] Step S402: If the deviation value and the average deviation value meet the first preset condition, then the average alarm deviation value is calculated based on the deviation value.

[0103] Specifically, if the deviation value and the mean deviation satisfy S N＝1 ≥2S average According to the formula The average alarm deviation S was calculated. average_warning .

[0104] Step S403: Determine whether the average deviation and the average alarm deviation meet the second preset condition: if yes, determine that the cable sheath is damaged; if no, determine that the cable sheath has experienced a single abnormal disturbance.

[0105] Specifically, when the mean deviation and the alarm deviation satisfy S average_warning <2S averageIf the mean deviation and the mean alarm deviation satisfy the second preset condition, then the second preset condition is determined.

[0106] Step S50: If the cable sheath is damaged, determine the location of the cable sheath damage based on the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum.

[0107] Specifically, the theoretical phasor values ​​of the sheath current at multiple target points in the sheath damage grounding full current information spectrum under different damage locations and different damage grounding resistance values ​​are formed into a data set;

[0108] Establish the minimum current norm I for sheath failure d Relationship:

[0109]

[0110] Among them, I g1_d I g2_d I c1_d I c2_d This represents the theoretical phasor value of the sheath current at a specific location and with a specific grounding resistance value within the dataset.

[0111] According to I d The minimum value determines the location of cable sheath damage.

[0112] Figure 3 , Figure 4 In the diagram, the horizontal axis represents different levels of grounding resistance, and the vertical axis represents the phase and amplitude of the sheath current. Each curve in the diagram represents the location of sheath damage points at intervals of 10% of the cable's total length, i.e., sheath damage occurring at positions 10%L, 20%L, ..., 90%L. Figure 3 , Figure 4 These represent the different phase θ and amplitude A of the sheath current under different locations and grounding resistance conditions. The phasor expression for the sheath current I is: I = Acosθ + jsinθ.

[0113] Due to measurement bias, it is necessary to select the optimal solution from the measured data to obtain the location of the breakage point. This is achieved by calculating the minimum norm of the four actual phasor values ​​and the theoretical phasor values ​​to obtain the location of the breakage point closest to the true value. The simulation results are shown in the table below.

[0114]

[0115]

[0116] The results above show that the calculation error of this method is within 5% when different grounding resistance failure events occur at different locations, and the method is reliable.

[0117] The cable sheath damage detection method in this embodiment of the invention first establishes a normal sheath current calculation model and a damaged sheath current calculation model; then, based on the normal sheath current calculation model, it calculates the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions; and based on the damaged sheath current calculation model, it calculates the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different grounding resistance values, and forms a sheath damage grounding full current information spectrum; then, it determines whether the cable sheath is damaged based on the actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath; finally, if the cable sheath is damaged, it determines the location of the cable sheath damage based on the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum. This invention can accurately determine whether the cable sheath of a long cable line is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath. Then, by using the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum, the location of the cable sheath damage can be determined, thus achieving accurate location of the sheath damage and improving the level of cable operation and maintenance.

[0118] See Figure 5 As shown in the figure, this embodiment of the invention also provides a cable sheath damage detection device, including: a modeling unit, a first calculation unit, a second calculation unit, a judgment unit, and a positioning unit.

[0119] The modeling unit is used to establish a calculation model for the normal sheath current and a calculation model for the damaged sheath current of the cable.

[0120] The first calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath according to the normal sheath current calculation model.

[0121] The second calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different damage grounding resistance values ​​based on cable parameters, load current, and damaged sheath current calculation model, forming a complete current information spectrum of sheath damage grounding.

[0122] The judgment unit is used to determine whether the cable sheath is damaged based on the actual phasor value and theoretical phasor value of the sheath current at multiple target points.

[0123] The positioning unit is used to determine the location of cable sheath damage based on the actual phasor values ​​of sheath current at multiple target points and the sheath damage grounding full current information spectrum if the cable sheath is damaged.

[0124] This invention provides a cable sheath damage detection device. First, it establishes a calculation model for the normal sheath current and a calculation model for the damaged sheath current. Then, based on the normal sheath current calculation model, it calculates the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions. Next, based on the damaged sheath current calculation model, it calculates the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different grounding resistance values, forming a complete current information spectrum of sheath damage grounding. Then, it determines whether the cable sheath is damaged based on the actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points. Finally, if the cable sheath is damaged, it determines the location of the cable sheath damage based on the actual phasor values ​​of the sheath current at multiple target points and the complete current information spectrum of sheath damage grounding. This invention can accurately determine whether the cable sheath of a long cable line is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath. Then, by using the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum, the location of the cable sheath damage can be determined, thus achieving accurate location of the sheath damage and improving the level of cable operation and maintenance.

[0125] It should be noted that those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the device and each unit described above can be referred to the corresponding process in the aforementioned embodiments of the cable sheath damage detection method, and will not be repeated here.

[0126] The cable sheath damage detection device provided in the above embodiments can be implemented as a computer program, which can, for example, Figure 6 It runs on the computer device shown.

[0127] This invention also provides a computer device, including: a memory, a processor, and a network interface connected via a system bus, wherein the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement all or part of the steps of the aforementioned cable sheath damage detection method.

[0128] The network interface is used for network communication, such as sending assigned tasks. Those skilled in the art will understand that... Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device to which the present invention is applied. A specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0129] A processor can be a CPU, or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor can be a microprocessor, or any conventional processor. The processor is the control center of a computer device, connecting all parts of the computer device through various interfaces and lines.

[0130] Memory can be used to store computer programs and / or modules. The processor implements various functions of the computer device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, at least one application program required for a function (such as video playback, image playback, etc.), etc.; the data storage area can store data created based on the use of the mobile phone (such as video data, image data, etc.). In addition, memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, SmartMedia Cards (SMC), Secure Digital Cards (SD cards), Flash Cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0131] In one embodiment, the processor is configured to run a computer program stored in memory to perform the following steps:

[0132] Step S10: Establish the calculation model for normal sheath current and the calculation model for damaged sheath current of the cable.

[0133] Step S20: Calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under normal conditions based on the normal sheath current calculation model;

[0134] Step S30: Calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different grounding resistance values ​​according to the damaged sheath current calculation model, and form a complete current information spectrum of sheath damage grounding.

[0135] Step S40: Determine whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath.

[0136] Step S50: If the cable sheath is damaged, determine the location of the cable sheath damage based on the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum.

[0137] This invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements all or part of the steps of the aforementioned cable sheath damage detection method.

[0138] The embodiments of the present invention can implement all or part of the aforementioned processes, or they can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various methods described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added to or subtracted according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0139] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, servers, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0140] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0141] The serial numbers in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0142] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0143] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method for detecting cable sheath damage, characterized in that, Includes the following steps: Establish calculation models for normal cable sheath current and damaged cable sheath current; The theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath are calculated based on the normal sheath current calculation model. Based on the damaged sheath current calculation model, the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath are calculated under different damage locations and different grounding resistance values, and a complete current information spectrum of sheath damage grounding is formed. Determine whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath. If the cable sheath is damaged, the location of the cable sheath damage is determined based on the actual phasor values ​​of the sheath current at multiple target points and the sheath damage grounding full current information spectrum. If the cable sheath is damaged, the location of the cable sheath damage is determined based on the actual phasor values ​​of the sheath current at multiple target points and the total current information spectrum of the sheath damage to ground, including: The theoretical phasor values ​​of the sheath current at multiple target points in the sheath damage and grounding full current information spectrum under different damage locations and different grounding resistance values ​​are used to form a data set. Establish the minimum current norm for sheath failure Relationship: When the power grid is cross-connected, multiple target points are the cross-grounding point and cross-connection point at both ends of a phase, and a phase. , , , These are the actual phasor values ​​of the sheath current at the cross-grounding point and the cross-interconnection point at both ends, respectively; , , , This represents the theoretical phasor value of the sheath current at a specific location and with a specific grounding resistance value within the dataset. according to The minimum value determines the location of cable sheath damage.

2. The cable sheath damage detection method according to claim 1, characterized in that, The method of determining whether the cable sheath is damaged based on the actual and theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath includes: The actual phasor values ​​of the sheath current at multiple target points are collected at preset time intervals. The deviation value and the average deviation value are calculated based on the actual phasor values ​​and theoretical phasor values ​​of the sheath current at multiple target points. If the deviation value and the average deviation value meet the first preset condition, the average alarm deviation value is calculated based on the deviation value. Determine whether the average deviation and the average alarm deviation meet the second preset condition: if yes, determine that the cable sheath is damaged; if no, determine that the cable sheath has experienced a single abnormal disturbance.

3. The cable sheath damage detection method according to claim 2, characterized in that, The process involves collecting actual phasor values ​​of sheath current at multiple target points at preset time intervals, and calculating deviation values ​​and average deviation values ​​based on the collected actual and theoretical phasor values ​​of sheath current at multiple target points. According to the formula: Calculation yields any Time deviation value ; According to the formula The mean deviation was calculated. ; When the power grid is interconnected, , , , These are the theoretical phasor values ​​of the sheath current at the cross-grounding point and the cross-interconnection point of the cable sheath under normal conditions; the preset time interval can be selected according to requirements. For the number of collections, Take 1~ .

4. The cable sheath damage detection method according to claim 3, characterized in that, If the deviation value and the average deviation value meet the first preset condition, then the average alarm deviation value is calculated based on the deviation value, including: If the deviation value and the mean deviation satisfy According to the formula The average alarm deviation was calculated. .

5. The cable sheath damage detection method according to claim 4, characterized in that, Whether the average deviation and the average alarm deviation meet the second preset condition includes: When the mean deviation and alarm deviation meet the requirements If the mean deviation and the mean alarm deviation satisfy the second preset condition, then the second preset condition is determined.

6. The cable sheath damage detection method according to claim 3, characterized in that, The establishment of calculation models for normal sheath current and damaged sheath current includes: The calculation model for normal sheath current of cable is established as follows: ； in, This represents the sheath current at the target point under normal cable sheath conditions. This represents the leakage current at the target point under normal cable sheath conditions. This refers to the induced current at the target point under normal cable sheath conditions. The calculation model for cable sheath damage current is established as follows: ； in, This refers to the sheath current at the target point when the cable sheath is damaged. This refers to the leakage current at the target point when the cable sheath is damaged. This refers to the induced current at the target point when the cable sheath is damaged.

7. A cable sheath damage detection device, characterized in that, include: Modeling unit, which is used to establish a calculation model for normal sheath current and a calculation model for damaged sheath current of cable sheath; The first calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath according to the normal sheath current calculation model. The second calculation unit is used to calculate the theoretical phasor values ​​of the sheath current at multiple target points on the cable sheath under different damage locations and different damage grounding resistance values ​​based on cable parameters, load current and damaged sheath current calculation model, and form a complete current information spectrum of sheath damage grounding. The judgment unit is used to determine whether the cable sheath is damaged based on the actual phasor value and theoretical phasor value of the sheath current at multiple target points; The positioning unit is used to determine the location of cable sheath damage based on the actual phasor values ​​of sheath current at multiple target points and the sheath damage grounding full current information spectrum if cable sheath damage occurs. If the cable sheath is damaged, the location of the cable sheath damage is determined based on the actual phasor values ​​of the sheath current at multiple target points and the total current information spectrum of the sheath damage to ground, including: The theoretical phasor values ​​of the sheath current at multiple target points in the sheath damage and grounding full current information spectrum under different damage locations and different grounding resistance values ​​are used to form a data set. Establish the minimum current norm for sheath failure Relationship: When the power grid is cross-connected, multiple target points are the cross-grounding point and cross-connection point at both ends of a phase, and a phase. , , , These are the actual phasor values ​​of the sheath current at the cross-grounding point and the cross-interconnection point at both ends, respectively; , , , This represents the theoretical phasor value of the sheath current at a specific location and with a specific grounding resistance value within the dataset. according to The minimum value determines the location of cable sheath damage.

8. A computer device, characterized in that, include: A memory and a processor, wherein the memory stores at least one instruction, which is loaded and executed by the processor to implement the cable sheath damage detection method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions that, when executed by a computer, cause the computer to perform the cable sheath damage detection method according to any one of claims 1 to 6.

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